Characterization and acidic properties of silica pillared titanates

Abstract

Reaction of alkylammonium titanates with tetraethylorthosilicate (TEOS) resulted in the intercalation and polymerization of TEOS between the titanate sheets. After heating to 500 °C, the basal spacing of pillared silica titanates increased with increasing length of the alkylamine chains and the amount of silicon intercalated. Although the layers of pillared titanates were expanded by the silica species, and the specific surface area increased, only negligible micropores were formed, suggesting that the interlayer region was “stuffed” with the pillaring species. The adsorption of pyridine indicated the formation of strong Brönsted acid sites up to 300 °C. In addition some basic Lewis sites were detected on silica pillared titanates.